Alcohol disinfection, the higher the concentration, the better the effect?-This statement is really wrong!

When it comes to medical alcohol, everyone is no stranger, this is a small family medicine box and medical institutions standing disinfection drugs. Hand hygiene is an important part of disease prevention during the fight against the new coronavirus epidemic.

In all kinds of disinfectants, the ability of alcohol should not be underestimated. However, many people have a misunderstanding about alcohol, that is, "the higher the alcohol concentration, the better the disinfection effect".

In fact, the concentration of alcohol for disinfection should be between 70% and 75%. If the concentration of alcohol is too high, it is not conducive to the penetration of alcohol into the pathogen and cannot achieve the disinfection effect.

The biggest advantage of alcohol is that the killing range is wide enough.

Methods for hand hygiene include: soap and water washing, hand sanitizer (alcohol-based hand sanitizer, etc.), foam or gel hand sanitizer, etc. Because alcohol is easy to use, does not stain, has an acceptable odor, starts quickly and has a wide range of antibacterial activity, it is more and more popular.

The most prominent advantage is that it is effective against a variety of pathogens.

According to the Centers for Disease Control and Prevention (CDC), alcohol is effective against most gram-positive and gram-negative bacteria, including multi-drug resistant pathogens, HIV, influenza virus, vaccinia, hepatitis B and C viruses. Experiments have shown that alcohol is very effective in preventing seasonal influenza, H1N1 and other viral and bacterial-based diseases.

High concentration will affect its permeability

Protein denaturation is the main mode of action of alcohol against microorganisms. Alcohol can change the spatial structure of pathogen proteins, irreversible denaturation and coagulation, resulting in the loss of activity of both structural and functional proteins, thus causing serious damage to pathogenic microorganisms.

At the same time, alcohol can also destroy the cell wall of bacteria. Alcohol has a strong penetration, and when the concentration is 60%-80%, this penetration is the best, it can enter the pathogen body, destroy the integrity of the pathogen, and cause the pathogen to lyse. However, when the concentration reaches 90%, the disinfection effect of alcohol will decrease. This is because too high concentration of alcohol can make the protein on the outer surface of pathogenic microorganisms coagulate quickly, and form a protective shell on the surface of pathogenic microorganisms, which prevents alcohol from further entering the interior of microorganisms, and cannot effectively exert the disinfection ability of alcohol.

In addition, alcohol can interfere with the enzyme system of microorganisms. Enzymes are essential catalysts for normal physiological activities and metabolism of various organisms. Studies have shown that ethanol can interfere with pathogen metabolism through direct effects on pathogen enzyme systems.

Different concentrations determine the occasions in which it works.

The alcohol commonly used in hospitals includes two concentrations of 75% and 95%, and the alcohol used for disinfection is 75%, which is commonly used for disinfection of skin and medical devices. It is worth noting that alcohol has a certain irritation, can not be used for mucosal and large wound disinfection.

95% alcohol is commonly used as fuel, found in a variety of alcohol lamps, alcohol furnace, can also be used for pathological tissue sections of the fixed and dehydration steps.

In addition, 40%-50% alcohol can be used to prevent bedsores. Long-term bedridden patients are prone to bedsores due to long-term compression of local tissues, continuous ischemia, hypoxia, and malnutrition of local tissues. Once bedsores are formed, it is difficult to heal. The use of alcohol when turning over and scrubbing can promote local blood circulation and help prevent bedsores.

Alcohol also has the effect of evaporating heat and promoting vasodilation, so alcohol with a concentration of 20%-50% is often used for physical antipyretic.

The correct use of alcohol can play a better role

It should be emphasized that liquor cannot replace medical alcohol. The alcohol concentration of most spirits is roughly 20%-65%, while the medical alcohol recommend concentration used for disinfection is 70%-75%. Liquor can not reach the effect of medical alcohol to kill microorganisms, but in the absence of alcohol, liquor can be used as an emergency treatment for disinfection.

During the outbreak, some people will spray the room with alcohol to achieve disinfection, but it is not necessary to do so.

The Centers for Disease Control and Prevention (CDC) has made it clear in its environmental guidelines and in its Guidelines for Disinfection and Sterilization of 2008 that the use of alcohol for environmental disinfection is not recommend. This is because the disinfection area is too large, the alcohol evaporates fast, and the contact time with the surface of the object is short, which can not achieve a good disinfection effect.

To resist the virus, it is more important for us to wear masks when going out, ventilate the house frequently, wash hands frequently and minimize going out. At the same time, we should strive to enhance our own immunity and not gather in dense crowds. When conditions permit, alcohol can also be used reasonably for disinfection to protect themselves and their families.

alcohol can be used to wipe the phone screen?

During the epidemic, a variety of disinfectants and cleaners containing alcohol became a regular home stock. However, when we hold mobile phones in our hands every day, it is easy to be infected with various pathogens. Since various cleaning agents containing alcohol can clean oil stains and kill germs, is it not the most appropriate to use them to wipe LCD screens?

The truth is true, but if you wipe it incorrectly, it is likely to damage your mobile phone or other electronic devices.

Because, the use of alcohol to wipe the LCD screen, it is likely to make the screen by irreversible serious damage.

Why does alcohol have a strong corrosive effect on the LCD screen? The LCD screen is composed of multilayer materials, the core of which is a sandwich structure with a layer of liquid crystal molecules sandwiched between two polarizers. Both the polarizer and the liquid crystal molecules themselves are very soluble in alcohol. Once they are eroded by alcohol, they will dissolve immediately and the screen will become mottled.

However, modern LCD screens, especially touch screens, are not so fragile. Because we will also set a layer of glass cover on the top of the screen, this layer of cover plate mainly plays a role in preventing scratches from damaging the screen, and it can naturally block all kinds of moisture and solvents from the outside from directly contacting the structure below.

But even so, it is also a hidden danger to wipe the screen with a detergent containing alcohol. There are two main reasons:

First, the surface of the glass cover is actually coated with a special organic film, such as an oil-repellent film, which can reduce grease adsorption and alleviate the effect of fingerprints on the screen. Most of these coatings are various organic compounds, and their resistance to alcohol is very weak. If you add external force to wipe, the coating will fall off more easily, causing the screen to become flower. Of course, if the screen of the mobile phone is covered with film, then there is no need to worry too much about this problem.

Second, although the top of the LCD screen, that is, its surface is not so delicate, but its side is still very fragile. Most of the LCD screen damaged by alcohol is actually because the alcohol penetrates into the gap on the side of the screen, which is equivalent to avoiding the glass panel and directly drilling into the lower structure. Alcohol has weak surface tension and strong capillary effect. Once there is a gap that can be drilled, it will quickly invade it, and the consequences are naturally very annoying. If a small amount of alcohol enters the screen, you can immediately turn off the device to dry or blow dry with a hair dryer, which will not affect subsequent use.

Therefore, when the screen of our computer, tablet or smartphone needs to be cleaned, we can spray some special LCD screen cleaner and wipe it with a soft cloth to make the screen look new. The LCD cleaner has a very good removal effect on fingerprints and oil films, and many wet wipes also have similar functions.

The active ingredients of these cleaning products are mainly surfactants, which have a good cleaning effect on oil stains and will not damage various organic coatings. If there is no similar cleaner, the LCD screen can also be cleaned with a damp cloth dipped in a very small amount of pure water, but be careful not to let water flow into the gaps around the screen.

To sum up: if it is only for cleaning, it is safest not to use alcohol; If there is a need for disinfection, care should be taken. Some mobile phone products will be nominally disinfected with alcohol. It is recommended to read the instructions before disinfecting the mobile phone. In addition, when disinfecting the mobile phone with alcohol, it is recommended to stick the alcohol on a soft cloth first and wipe it gently with a soft cloth. Do not spray or pour alcohol directly onto the screen to prevent alcohol from flowing everywhere, increases the risk of damaging the phone by eroding the original screen.